A canister type vacuum cleaner is well known in the prior art and generally includes a canister portion, an upper portion to cap the canister and a base or platform portion upon which the canister rests and is thereby capable of movement. The base portion generally includes rollers, casters or wheels located at three, four or more points on the outer perimeter of the platform. Each caster or wheel is capable of swiveling through 360.degree. in order that the vacuum may be pulled in any direction and thereby roll in that direction. Canister vacuums are useful in any environment. However, canister vacuums are particularly applicable to areas in which standard upright vacuums, well known to those in the prior art, cannot reach. Such areas include small confined areas where a standard upright cleaner will not fit or cannot access, such as in corners or on stairs. Additionally, canister vacuums generally are capable of creating greater vacuum pressure in order that larger particulate matter may be removed from a vacuumed surface. Thus, a canister type vacuum cleaner presents many advantages over other available vacuum cleaners known in the prior art.
A canister type vacuum cleaner, as discussed above generally is comprised of three separate sections, the base, the canister portion with the filter therein, and a cover portion. Cover portions generally includes a fan and a motor for driving the fan in order that vacuum pressure is created within the canister. The cover also forms an enclosed cylinder when placed upon the canister. The canister is generally a cylinder having a flat bottom with a filter placed therein. When the filter becomes clogged through use and/or the canister becomes filled with particulate matter, the cover is removed, the filter is cleaned and/or replaced and the canister is emptied. Thus, the vacuum is again available for use and optimum vacuum pressure is restored.
Certain vacuums in the prior art include a cover, canister and base optimally held together by means of straps running generally parallel to the central axis of the canister. The straps are fastened by means of clamps, buckles or snaps or any other means known in the prior art. Thus, when completely assembled, the canister vacuum has a cover and a platform base with the canister interposed therebetween. This presents problems when it is desired to remove the cover to replace the filter or empty the canister. When the clamps are undone, the straps are unfastened and the cover is removed, the base is also removed from the canister. When it is time to reassemble the three parts, the canister must be placed on the base and the cover must be aligned with points on the base in order that the straps may be placed in their correct location. This can be time consuming, tedious and frustrating to any vacuum operator.
Other canister vacuums in the prior art also include three parts; a cover, canister and base in which the cover is connected to the canister by one set of fasteners, while the canister is connected to the base by a different set of fasteners. With such arrangement, the platform base may be removed and the vacuum may still be operated without the base. However, the fasteners between the canister and the base of these prior art vacuums are difficult for a vacuum operator to use. They require the vacuum operator to stoop over low to the ground to fasten or unfasten, as well as requiring alignment between points on the canister and points on the base before the fasteners can be latched. This disadvantage is both time consuming and tedious. In order to avoid the above disadvantages, three part canister vacuums have also been constructed with a cover connected to the canister with fasteners and a separate base, upon which the canister is placed. There are no fasteners provided to keep the canister on the base. Instead the base is provided with a depressed receptacle within which the canister is placed. A circumferential lip on the platform base prevents the canister from sliding off the base. Thus, the vacuum is moved about the floor using rollers on the platform base by pulling on the vacuum hose. However, there are also distinct disadvantages in this design. For instance, the vacuum cannot be picked up as a unit, since, in attempting to do so, the base will fall off. However, even when the vacuum is being pulled around using the hose, the vacuum tends to come apart since it often turns over upon hitting the edge of a rug or some other obstruction on the floor.
In order to solve prior art problems, it has been suggested in the prior art to provide a canister type vacuum cleaner having only two parts, a cover, including the motor and fan unit for creating vacuum pressure, and a canister having an integral or homogeneous base or platform unit provided with casters or wheels in order to allow movement of the canister from place to place during operation. Thus, when it becomes necessary to empty the canister or change the filter, the cover, provided with any of a number of known clamps, snaps or buckle fasteners is removed allowing the canister to be accessed and emptied. Because the base is an integral part of the canister, placing the cover on the canister is easy and no longer time consuming. However, in certain instances a canister type vacuum cleaner with its versatility and high vacuum pressure is desired to be used in areas where a base having wheels or casters is a detriment or adds unnecessary weight. Such areas may include a sloped surface, where it is desired that the canister remain stationary, as in outdoor applications, or in high areas which are hard to reach and in which the canister must be lifted off of the ground due to the length limitations of the vacuum hose, i.e. vacuuming draperies or vacuuming stairs or carpeted stairs where the canister needs to be carried along the stairs.
Canister vacuums are especially useful on stairs, where the vacuum hose and wand portion can access every corner for efficient cleaning. However, prior art canister type vacuum cleaners are virtually impossible to use on stairs without the operator carrying the full weight of the canister along the stairs. This requires the vacuum operator to perform unnecessary work. Prior art canister type vacuum cleaners having an integral base with wheels or casters will not stay on the stairs, as these type vacuum cleaners have the tendency to roll off of the stairs. Prior art canister type vacuum cleaners in which the base and cover are separable parts having common straps connecting them to the canister are also not adequate for stair or similar vacuum operations. In those prior art vacuums, the base can only be removed upon removal of the straps which also hold the cover in place over the top of the canister. Thus, the base of the vacuum cannot be removed without disassembling the entire vacuum assembly, making the canister type vacuum inoperative. Even in those prior art canister vacuums having fasteners between the cover and the canister and either separate fasteners between the base and the canister, or a base on which the canister sits without fasteners, enabling a user to remove the base without removing the cover, the canister type vacuum would still not be able to be placed effectively on a stair. Generally, the size of canister type vacuums is such that when placed on a standard size stair tread, the center of gravity of the vacuum is over the edge of the stair and the canister vacuum will tend to fall off of the stair. Reducing the size of a standard canister vacuum detrimentally reduces the available vacuum pressure.